Are you tired of sounds seeping into your room and disturbing everything you’re doing? Trying to stop flanking noises, and you’re wondering what works best? An acoustical sealant will improve the sound experience within a room.
Wondering what the best acoustical sealant is? The best acoustical sealant adheres to most types of construction material and stays supple and flexible for decades. It will block out irritating flanking noises and provide better sound attenuation. The sealant is an essential component for soundproofing any room.
In this article, we identify what acoustical sealant is and how and where to apply it for the best results. We look at what makes a good acoustic caulk and what to consider when making a purchase.
We also review seven available products. When you’re finished reading, you should have a better understanding of how acoustic sealant works, where and how to apply it, and which product is best.
What Is Acoustical Sealant?
An acoustic sealant is a specialized sound-absorbing soundproofing caulk that adheres to most building materials – wood, metal, gypsum, and concrete. It is a water-based, non-flammable, non-toxic, low odor substance that is even freeze-thaw stable. The rubbery material can even handle seasonal expansion and contraction of materials.
The sealant provides a permanently flexible seal against soundwave penetration and stays pliable. It doesn’t dry out, harden, shrink, or separate from adjoining surfaces like regular caulking. It can be taped, spackled, and painted too.
Acoustic Caulk vs. Regular Caulk
Sound travels in wave patterns. The low frequency has greater distances between the wave crests and is harder to block, high frequencies have short distances between crests, and mid-ranges are in between. When the wave encounters a barrier like a wall, it may reflect in a different direction, find a hole or crack and sneak through, vibrate through the material, or bounce around until it can travel on or is converted to heat energy.
Airflow or leakage through or around a wall, ceiling, or floor is accompanied by noise infiltration. Anywhere air can go, sound can go too. So the main difference between acoustic and regular caulk is how effectively they block the movement and how durable and permanent they are. However, it isn’t just about stopping airflow; it’s also about absorbing vibration.
A regular sealant may stop air movement initially, but not sound vibration. Acoustic caulking has several important differences that make it much more effective and dependable at stopping noise transmission and vibration. It is non-hardening and is permanently flexible, so it stops penetration by noise vibration.
Acoustic caulk doesn’t dry, shrink, or crack like regular caulk and will prevent noise and air seepage. It is a durable and long-term noise solution.
What is the Difference Between Noiseproofing Compound and Sealant?
The difference between the acoustic or noise-proofing sealant and the compound is in the formula. Whether the compound is in a tube or bucket, it is formulated to minimize sound transfer by changing soundwaves into heat, thereby damping the sound.
The compound is a viscoelastic material applied between two layers of drywall or other soundproofing materials in walls, ceilings, or floors. It can take up to 30 days to fully cure and reach its decoupling sound attenuating potential, which it will maintain for decades.
The acoustic sealant comes in a tube and has a cure time of 48-hours. The sealant provides an acoustic barrier that prevents penetration by sound, air, and moisture. The compound creates a 3-dimensional anti-vibrational noise-blocking separation that absorbs low, medium, and high-frequency sound waves. The sealant and compound are used for different purposes but combine to soundproof a room effectively.
Where to Use Acoustical Sealant?
An acoustic sealant is used to fill seams, small cracks, and crevasses to prevent air and soundwave infiltration. It should be used around the perimeter joints of drywall sheets before taping and mudding. That includes sealing the gap where walls meet each other and the ceiling or the floor to prevent sound transmission or movement around the partition.
The sealant should be used to close any openings around ductwork, wire or plumbing holes, PVC or metal pipes, electrical boxes, recessed lighting, windows, and doors. Anywhere air can penetrate, sound can too. Using an acoustic sealant will provide a barrier to flanking sound and thermal transfer.
Best Acoustic Sealant for Noise Reduction
Selecting a soundproof caulk can be confusing and frustrating. The printing on labels and fact sheets seems to be smaller, and the wording more difficult to understand. Here we provide a clear explanation of seven products that acoustically seal and improve sound attenuation when applied correctly.
1. Green Glue NoiseProofing Sealant
Green Glue noise proofing sealant fills cracks, gaps, and seams 1/8” to 1/4″. It is ideal for around electrical boxes, doors, and windows to prevent sound transfer too. Seal around HVAC openings, and even along metal ducts to minimize vibration and noise movement.
Use it to block low-frequency waves, plus mid and upper range noise. When cured, it is pliable and elastic, which makes it acoustically beneficial for soundproofing.
The white color sealant sticks to everything with gooey elasticity, including vapor-barrier. It is non-toxic, mold and mildew resistant, and the low odor smell will disappear when it is cured and paintable – within 48 hours. The sealant can also be taped and mudded over. It shouldn’t be used for exterior applications or around plumbing or water pipes.
Clean-up, before it cures, is easy with soap and water. After it cures, peel it off with your hand and clump it into a tacky, spongy ball. It is available in singles or sets of six 29 oz tubes. Green Glue sealant improves soundproofing and reduces noise transmission. It improves the sound transmission class (STC), which assists in the acquisition of LEED certification.See Prices >
2. TMS Acoustical Caulk
Use TMS Acoustical Caulk for gaps, cracks, and seams where sound may penetrate through a wall. The caulking prevents sound leakage by remaining flexible and sealing openings where noise transfer occurs.
It reduces drywall and plaster vibration, helping to eliminate mid to high-frequency transmission through walls.
The latex-based white-colored compound is non-flammable, fire-rated, and mold and mildew resistant. It is VOC compliant and environmentally safe too. However, it isn’t heat rated, so it shouldn’t be used around hot pipes or ducts. The cure time is greater than 48 hours, and it isn’t paintable until well cured.
The sealant is available in single 29 oz tubes. Before it cures, it can be cleaned up with water. The TMS Acoustical Caulk remains flexible and improves soundproofing by preventing air movement through or around barriers.See Prices >
3. Auralex Acoustics STOPGAP Acoustical Sealant
STOPGAP sealant seals cracks and gaps around walls, floors, ceilings, windows, and doors. It will cover approximately 32 linear feet with a 3/8” bead and 80-feet with 1/4″ bead.
It holds its elasticity and pliability when cured to prevent sound wave penetration, helps to decouple partitions, thus improving soundproofing.
The water-based, white-colored sealant is highly elastic, waterproof, flame retardant, and non-staining. There is no slumping or run-off, so it works well to seal around lighting, switch, and receptacle boxes to damp sound.
When applied following ASTM C-919 guidelines, STOPGAP can improve wall STC rating to 53. When cured, it has a flexible surface film that is paintable. The acoustic sealant comes in 28 oz singles or cases of 12. When wet, the sound caulking can be cleaned up with water.See Prices >
4. TMS Acoustical CaulkTMS Acoustical Caulk adheres to drywall, concrete, wood, and metal. It prevents sound leakage, drafts, and smoke penetration when used to fill gaps, cracks, and crevasses. The sound sealant remains flexible and doesn’t shrink, crack, split, or dry out, contributing to its soundproofing qualities. It even withstands the freeze-thaw of seasonal temperatures.
The white latex-based caulking is low toxicity, high adhesion, mildew, and mold-resistant, and paintable. Used around the perimeter of walls and drywall and to fill gaps around electrical openings and cut-outs.
It can improve the STC rating to 52, assisting in LEED compliance. The acoustical caulk takes 3 to 7 days to cure, depending on application temperature and humidity.
TMS caulk is available in 28 oz plastic single tubes that can be bought in quantities of 1, 6, or 12. Clean excess, when still wet, with paper towels or dry cloth and mineral spirits or acetone. When cured, scrape or cut the excess off.See Prices >
5. Tremco Acoustical Sealant
Tremco Acoustical Sealant works to seal flanking sound movement around the wall and other barrier construction. Used around wall perimeter joints and seams and to seal the vapor barrier, it will damp noise transmission and improve the STC of a wall system up to a rating of 60. The sealant is suitable for sealing everything from drywall partitions to corridors.
The synthetic sound damping rubber composite polymer is gray to dark gray and sticks to most building materials. The wall sealant doesn’t cure and will stick to anything and will collect dust too.
It doesn’t skim, harden, or dry and should be covered within 24-hours to prevent contamination or mess. The compound stays tacky and viscous, improving its damping abilities.
The sound sealant is available in a 24.7 oz tube. To clean excess tools and smears using paper towels with mineral spirits or xylene. The work site should be well ventilated, and protective gloves are recommended.
6. OSI SC175 Draft and Acoustical Sound Sealant
OSI acoustical sealant damps sound movement through floors, walls, and ceilings. It can be applied around wall and panel perimeters, cut-outs for electrical and lighting, and HVAC apertures. Caulked or buttered, it will improve the partition STC rating to 55 when used with other soundproofing materials. A tube will do 86-feet of 1/4″ bead and 38-feet of 3/8” bead.
SC175 is a low odor white latex rubber base non-slumping paste that stays supple and flexible. It complies with VOC requirements and is non-flammable. The caulk adheres to drywall, concrete, wood, metal, and most other structural building materials.
It is an effective seal for sill, base, and top plates to help prevent flanking. The sealant is tack-free in 30-minutes, paintable in 24 hours, and cures in 2 to 7 days.
The sound sealant is available in boxes of 12 tubes or 28 oz singles. Before it cures, clean up with soap and water. Once cured, it can be scraped or trimmed with a sharp blade. Gloves are recommended when using a sealant.See Prices >
7. LIQUID NAILS AS-825 Acoustical Sound Sealant
AS-825 sound deadening acoustical caulk helps to prevent drafts and sound transmission through walls and around doors and windows. Use it to seal around electrical and lighting boxes, wall, and panel perimeter joints to improve the partition STC rating. A 28 oz cartridge will do a 1/4″ bead for 86 linear feet and about 40 feet of 3/8” bead.
The ethylene-vinyl acrylic water-based latex soundproofing caulk adheres to most building materials, except PVC, non-porous surfaces, and plastics. It remains permanently flexible and is non-flammable, low odor, and VOC compliant. The white paste is tack-free in 20 minutes and is fully cured in 24 to 72 hours.
Liquid Nails acoustic sealant is available in 28 oz cardboard tubes in one, two, three, four-packs, or boxes of 12. Clean up of tools and mess when wet is easy with water and a rag or paper towels. After curing, scrape, or trim with a utility blade.See Prices >
How to Apply Acoustic Sealant
An acoustic sealant is one component used when minimizing sound movement in or out of a room. The magnitude of your soundproofing project determines how the sealant is applied and how effective it will be at stopping flanking noise transmission. When used with other soundproofing materials in wall, ceiling, and floor construction, the STC rating increases.
When applying acoustic sealant, the surfaces should be free of dirt, dust, and moisture. Use a utility knife or scissors to trim or clean the hole or crevasse if necessary to ensure the desired contact surface.
If it’s too small to get the paste inside the crack or hole, an effective seal may not be created. A 1/4″ to 3/8” opening is best, cut the nozzle opening for the desired bead diameter. Apply the caulk to the hole or crack. Clean the excess or mess with a cloth, paper towel, finger, or tool within 15 to 30 minutes of application before it skins over.
For cracks or openings larger than 1/2″, a backer rod is recommended before filling with acoustic caulk. Fill the larger openings around doors, windows, electrical boxes, HVAC openings, and lights working from the outside edges in with multiple beads or layers as required for a complete seal. Allow the sealant to cure before trimming and painting.
When adding a new layer of gypsum to an existing wall, leave a gap at the floor, ceiling, and adjacent walls. Clean the contact surfaces of dust and dirt.
Fill the gaps and perimeter joints with soundproof caulk to block sound transmission. Ensure there is full contact and an unbroken seal – even a small opening can allow sound to leak through.
Sealing new wall assemblies with acoustical caulk will provide the best soundproofing seal. However, the rest of the wall, floor, and ceiling construction should include the best noise-reducing building practices and materials.
For the most effective seal, a thick bead should be applied under the plate and around the perimeter of each layer of drywall. Serious soundproofing comes with a hefty price tag – five or more perimeter beads per wall add up to a lot of acoustic sealants, but the reward is the sound of silence.
What to Consider Before Buying Acoustic Sealant
Many products claim to be acoustic caulk or sealant. Make sure to read reviews and do some online reading to check if your choice meets your requirements. Select one that stays supple, flexible, and won’t harden or shrink and pull away at the edges.
Remember, an acoustic sealant is only one component of soundproofing – drywall, insulation, putty pads, isolation clips, resilient channels, and acoustic compound complete the effort.
Some sealants will adhere better to different construction materials while others can dissolve plastic vapor barriers; read the label for compatibility. The elasticity and viscosity are other impacts of ease of application. Filling large gaps or small cracks will determine which is more workable.
Solvent-based and water-based products are another issue. Water-based is easier to clean up, non-toxic, has less odor, and has no VOC. Some are waterproof and work better for damp areas, and check for interior-exterior compatibility. Additionally, most applications are covered by trim or mudding; however, select a paintable or colored caulk for visible installations.
Price and coverage may be deciding factors between comparable products. Most will cover 85 linear feet with a 1/4″ bead per 28 or 29 oz tube, or 40 linear feet with a 3/8” bead. The tubes are larger and use a bigger applicator.
With a cost range between 7₵ and 40₵, sealing a window or door versus soundproofing the construction of a wall barrier will determine how many tubes and the cost impact. The more you need or less frugal your application, the less costly may be a better choice.
Soundproof caulking is an important part of preventing flanking noise through and around wall elements. The best acoustical sealant stays flexible and pliable permanently, sticks to everything, seals wall perimeters around utility boxes, and is easy to clean up.
My recommendation is Green Glue NoiseProofing Sealant. It meets all the criteria for the best sound controlling sealant, plus it blocks low-frequency sound waves, as well as mid and high range waves.
Hopefully, you now know what to look for when selecting an acoustic sealant for your project. Understanding what acoustic caulk or sealant is and how it works should make your task easier. If you found the article helpful, share it with others who may appreciate it too. Your comments and suggestions are always appreciated.
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